Perky Posted November 14, 2005 Share Posted November 14, 2005 I have a strange problem. When I let off the throttle, release the handle bars, and I decelerate below 45mph I get a wobble in the front end. I can let go of the bars at 100mph and there isn't any wobble. But as soon as I reach the 45mph mark, the front begins to shimmy like crazy. I can release the handle bars at 45mph and again it is rock solid. No shaking at all. It is only when I decelerate down through the 45mph mark Anyone ever have this phenomenon before? I know the easy answer is to just not let go of the bars. I think it is the Dunlop tires I have on the Bird, but I am not sure. I am switching out the rear to a Michelin Pilot Road this weekend, but my front is still in great shape. I will let everyone know if switching the rear helps out. Alright guys, post up with any suggestions. Quote Link to comment Share on other sites More sharing options...
Redbird Posted November 14, 2005 Share Posted November 14, 2005 You by any chance running a Givi top box? Quote Link to comment Share on other sites More sharing options...
Perky Posted November 14, 2005 Author Share Posted November 14, 2005 No, just a plain stock setup. Nothing extra. Quote Link to comment Share on other sites More sharing options...
Perky Posted November 14, 2005 Author Share Posted November 14, 2005 I guess I should include some more info. 2003 Stock Blackbird Dunlop front and rear (2nd set) 13,500 miles Never changed fork oil. Stock chain and sprockets.(Chain and sprockets are still in great shape.) On a side note, I am done with the Dunlops. As I said earlier, I am switching the rear to a Michelin Pilot Road this weekend, and as soon as the front wears down, I will switch the front to the Pilot Powers. -Steve Quote Link to comment Share on other sites More sharing options...
Involute Posted November 14, 2005 Share Posted November 14, 2005 Loose or notched head bearings is my guess. Unless you like to wheelie I'd bet loose. Quote Link to comment Share on other sites More sharing options...
Redbird Posted November 14, 2005 Share Posted November 14, 2005 Checking the steering head bearing is definitely on the troubleshooting list, along with front wheel balance and rear wheel alignment. Quote Link to comment Share on other sites More sharing options...
bajjer9 Posted November 14, 2005 Share Posted November 14, 2005 Well I had plenty of tread on the dunlop front when I bought mine early in 03 and it acted the same way...It dissapeared completely when I put road pilots on...mine is a 97 by the way Quote Link to comment Share on other sites More sharing options...
Flitemdic Posted November 15, 2005 Share Posted November 15, 2005 Let us know how the switch out for the back works or whatever else you try please. I have the EXACT same problem with Sportmax's on right now. Mine is somewhat tire pressure dependant- if I go to exact measurements every single ride more than just to work, (42psi), it is somewhat less, but still there. I tried some of the above suggestions, no better, I didn't figure the tires until recently- I've always used the Sportmax, and have changed other parts- rims, etc, but there isn't really much else I can switch out. Quote Link to comment Share on other sites More sharing options...
Skull Posted November 15, 2005 Share Posted November 15, 2005 I have the same problem with a set of Avons. The steering head bearings will be checked for tightness ASAP. I don't wheelie much, and rarely on purpose, but that doesn't mean the former owner didn't. :? Quote Link to comment Share on other sites More sharing options...
Northman Posted November 15, 2005 Share Posted November 15, 2005 I had this problem a long time ago, with the stock Michelin, as well as the 2 Avon's that replaced it. Replaced the steering head bearings with tapered over 20K ago, and no problem since. Quote Link to comment Share on other sites More sharing options...
diputsnyc Posted November 15, 2005 Share Posted November 15, 2005 You by any chance running a Givi top box? Why did you ask? I have a givi top case. I had the same problem decelerating at 37 mph. I was going to check the steering head bearings, but when I replaced the tires, the problem seemed to go away. I still need to change the front fork springs. When I do the front, I should just replace the bearings and be done with it. Quote Link to comment Share on other sites More sharing options...
arcticflipper Posted November 15, 2005 Share Posted November 15, 2005 I picked up this problemon a stock 02 with stock suspension front and rear. Running Maxxis supermax tires front and rear. I noticed that on a occasional wash that the font left disc was more loose than the right - when standing in front of the bike. I think it's called rotars?? I could actually move the front floating disc backwards, forwards, side to side easily. I had this reseated and clamped through the local bikeshop, and the problem has now become a lot less. I still get a wobble every now and then, but mainly if I let go of the bars, and rests my foot on the rear brake. The wabble I think comes from the linked brake system that might need to be checked and bleeded. The linked brake system builds up pressure on the rear brake, and this I think then moves over to the front piston connected to the system. The pressure is not even through on both pistons, thus the wobble. But then on the other hand I could be completely wrong here. Still have to bleed the brakes, look at the front brakeshoes and discs, and then I will be able to verify my theory. Quote Link to comment Share on other sites More sharing options...
EVLXX Posted November 15, 2005 Share Posted November 15, 2005 Simple.... Your tire is CUPPED! It's a given with Dunlops and Avons. PR's are smooth. Quote Link to comment Share on other sites More sharing options...
beondwacko Posted November 15, 2005 Share Posted November 15, 2005 I had the same problem decelerating at 37 mph. I was going to check the steering head bearings, but when I replaced the tires, the problem seemed to go away. Â Same thing here. I went from the OEM BT's to the Pilot Roads and it all went away. The bars are steady now at any speed hands off. Quote Link to comment Share on other sites More sharing options...
Pete in PA Posted November 15, 2005 Share Posted November 15, 2005 As North said, change to tapered and never have the problem again. ALL bikes SHOULD come with tapered from the factory but few do. There are a lot of dynamics going on to create that decell. wobble. tire wear/brand, front end weight, rake and trail, allignment, etc. they all interact together to create the wobble, but the steeringhead bearings ARE the cause. Quote Link to comment Share on other sites More sharing options...
blackhawkxx Posted November 15, 2005 Share Posted November 15, 2005 I bet a new front tire will fix that even if it is a Dunlop. Quote Link to comment Share on other sites More sharing options...
Perky Posted November 21, 2005 Author Share Posted November 21, 2005 Well, here is an update after installing the Michelin Pilot Road. The Pilot is absolutely great, but it didn't solve the problem. Actually, it appears it actually made the front end wobble a little worse. I was really hoping swapping the tire would solve the problem. I won't have time before Thanksgiving to swap the Head Bearings, so after I get back from FUXXT, I will replace them and post another update. Thanks for all the advice on this. You guys are great. -Steve Quote Link to comment Share on other sites More sharing options...
JasonW Posted November 21, 2005 Share Posted November 21, 2005 I'm not surprised that changing the rear to a PR didn't help......mismatched tire sets have been known to cause a wobble. Like others have said, it's either the front tire or the steering head bearings. It won't hurt anything to change the bearings, but I wouldn't expect it to be a complete cure until the front tire is changed. Dunlops seem to begin cupping after the first 2 revolutions. Quote Link to comment Share on other sites More sharing options...
TFT Posted November 21, 2005 Share Posted November 21, 2005 What is a good source for tapered bearings? Quote Link to comment Share on other sites More sharing options...
Justin Posted November 21, 2005 Share Posted November 21, 2005 as others have said .. .cupped tire ... I always get it with Dunlops on the front. Not when they are new, but towards the second half of their lives. Michelins and Conti's don't suffer as badly from this. I ussually run a D220 in the rear and a conti or michelin up front. Quote Link to comment Share on other sites More sharing options...
Perky Posted November 21, 2005 Author Share Posted November 21, 2005 I am going to wait to change out my front tire, but I think I will go ahead and replace the head bearings with a set of tapered ones. I found this site, and they are charging $34.95 for the tapered bearings. Is this a good price, and how difficult is it to replace them? http://www.crc2onlinecatalog.com/steering_...ad_bearings.htm -Steve Quote Link to comment Share on other sites More sharing options...
lmmb Posted November 21, 2005 Share Posted November 21, 2005 First, change the front tire Second, look top-case and take away and test the bike. Quote Link to comment Share on other sites More sharing options...
jrdxx Posted November 21, 2005 Share Posted November 21, 2005 I would just stick with the easy answer you already mentioned. It's good practice to check steering head bearing adjustment and front tire wear and balance, but I think anything else is overkill, and probably not worth the bother. There is an inverse relationship between stability and maneuverability with motorcycles, just as with aircraft. Front line fighters and aerobatic aircraft are inherently unstable, but this allows them to be highly maneuverable. Inherently stable aircraft, like transport category aircraft, maneuver like trucks-very large trucks. The same is true with motorcycles. The manufacturer must strike a balance between stability and maneuverability using steering head angle, rake and trail measurements according to the expected use of the particular model. I have noticed the oscillation at approximately the same speed on many road bikes, and as long as I can dampen and control the oscillation with light hand pressure on the bars, I don't worry about it. Now if the bike wanted to go into a tankslapper or weave at that speed, I would truly be concerned. Quote Link to comment Share on other sites More sharing options...
Texhoss Posted November 22, 2005 Share Posted November 22, 2005 Old bike did the same thing. It was a bad front tire. It was a new tire that the dealership mounted and balanced! Texhoss Quote Link to comment Share on other sites More sharing options...
sfarson Posted November 24, 2005 Share Posted November 24, 2005 Same here. Front end wobble on the XX and a Buell. Both caused by a poor tire up front. Solved with a replacement. Quote Link to comment Share on other sites More sharing options...
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